Acoustic Research AW-811 Indoor/Outdoor Wireless Speaker (single) Patented 900 MHz wireless technology transmits signal through walls, floors and ceilings at distances of up to 300ft Water-resistant for outdoor and indoor use, and in humid areas such as kitchens and baths Omnidirectional, auto-tuning speaker will conveniently tune to the transmitter at the touch of a button 3-in-1 power/volume/scan control combines controls into one easy-to-use knob Battery or cable-powered, with a foldable handle that makes moving easy